Upsilon (letter)

Upsilon (/ˈʌpsɪlɒn, ˈjuːp-, ˈuːp-, ˈʊp-, -lən/; or UK: /ʌpˈsaɪlən, juːp-/; uppercase Υ, lowercase υ; Greek: ýpsilon [ˈipsilon]) is the 20th letter of the Greek alphabet. In the system of Greek numerals, Υʹ has a value of 400. It is derived from the Phoenician waw .

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